The importance of last week’s “Brexit” vote cannot be diminished, even by those on our side of the Atlantic who insist on seeing only its possible effects on our November presidential election.

In defining the importance of Brexit, the reactions within the EU are a good place to start. Brit PM David Cameron, having staked everything on his campaign to remain in the EU, has said he’ll resign in October. Cameron wants the UK to wait until a new leader is chosen to begin the formal process of getting out of the EU under Article 50 of the Lisbon Treaty, the EU’s primary treaty.

The first members of the EU — France, Germany, Luxembourg, Belgium, Italy, and the Netherlands — reacted in panic. They fear, quite rightly, that the Brexit vote presages other nations’ exits from the EU. They insist that the Brits immediately invoke Article 50 to start the clock on its two-year deadline for any nation exiting the EU to negotiate its way out.

The 27 remaining EU nations will want to penalize Britain for its exit. Only Germany’s Angela Merkel has said the split from Britain needn’t be nasty. But she won’t be able to control the others.

The EU’s primary members will, as the negotiations roll out, insist on imposing tariffs and other trade restrictions on the UK. That they want to penalize the second-largest economy will affect them all negatively (as Merkel realizes). But the EU “powers” will make it as costly as they can, in economic and political terms.

They will try to insist on some form of open border agreement and with it some version of the EU’s human rights laws.

That will make it enormously difficult for the UK to succeed in its exit negotiations. Or will it?

Now that the UK Parliament is in control of the matter, it can do several things that will unwind the UK from the EU. It should begin immediately and proceed deliberately.

For example, the EU’s laws are integrated into those of the UK. The UK Parliament can, and must, repeal the European Communities Act which makes EU law part of the UK’s law. But the ECA is incorporated into the devolution statutes of Scotland, Northern Ireland, and Wales. To repeal the ECA will require consent of those parts of the UK. Scotland’s first minister, Nicola Sturgeon, has already said that Scotland will veto Brexit, and this is the way it will try to do so. Scotland may hold another devolution referendum itself, and there’s every reason to believe it could succeed. Northern Ireland could be next. In short, the UK itself could dissolve.

I’m betting it won’t because — with the exception of Northern Ireland which could join with the Irish Republic to its south — none of the UK’s other component nations could possibly survive independently. As independent as some Scots want to be, they couldn’t even support their socialized, government-paid health system without it being propped up by the Brits. They wouldn’t want the anti-democratic EU governing them any more than the Brits do. The issues they would face are exactly the same as those that drove the Brits to vote for Brexit.

David Cameron broke his pick trying to persuade voters that Britain should remain in the EU. His campaign predicted everything from massive job losses to war resulting from a pro-Brexit vote. His political coalition consisted of virtually every expert you can think of from every field. As Fraser Nelson wrote in the Wall Street Journal, Cameron rounded up every manner of politician, labor leader, movie star, spy chief, financial authority and historian — as well as President Obama — to campaign for “remain,” and it was all for naught. Why?

Immigration was clearly the biggest issue that caused the Brits to vote to get out of the EU. Immigration from EU nations — Romania, Poland, and others — has probably brought a million immigrants to the UK over the past decade. Brit voters saw the flood of refugees coming from terrorist-dominated nations in the Middle East into EU nations and wanted no part of that.

Second, they also wanted no part of the undemocratic way the EU imposed its will on the UK in virtually every area.

The nameless, faceless EU bureaucrats, EU courts, and EU parliament members regulated everything in British life from the power of hairdryers to Britain’s ability to deport suspected or known terrorists. As I wrote in February, in 2012 the Telegraph newspaper reported that the EU Court of Human Rights blocked 900 deportations of terrorists from the UK.

And it wasn’t just the “shadowy elite” of the EU courts and bureaucracy. It was also the showy elite of high-paid EU parliament members, flaunting their status. Pro-Brexit voters were simply fed up — as they are here and in many other nations — with governments that don’t answer to the people they govern.

That populism has taken root not only here and in the UK, but also in many EU nations.

The EU will fall apart entirely and it will take about a decade to do so. It simply can’t go on supporting the Greek and Italian economic disasters. We should be ready to engage in trade agreements with any nation that quits the EU and do so quickly if it’s in our national interest. It will be, almost without exception.

The effects of Brexit will ripple around the world. Before the vote, Obama said that the UK should go to the back of the line for a new trade agreement with the U.S. That’s precisely the opposite of what should happen, but it will in the remainder of Obama’s term and for the next four years if Hillary becomes president.

Donald Trump can capitalize on the Brexit vote, and he should in several ways. He should announce that a new trade agreement with the UK will be accomplished in his first one hundred days. That would send a powerful message to the UK, reversing Obama’s rejection of its friendship.

If, as he says, Trump really wants to reject and shake up the global elite, he could also say that he will reexamine our United Nations membership.

Trump always puts things in a business context, speaking about how much return we get for our investments. The UN is an enormously expensive toy of the globalist elite. The U.S. pays about $8 billion each year in dues and “voluntary” payments to UN organizations and gets nothing in return. Why, he should ask, do we pay so much and get so little? At least cutting our payments to the UN by 50 or 75 percent would be enough to get the UN’s attention and assert our own independence.

Unless Trump does these things, the significance of the Brexit vote will be very small in the November election.